Some bones rotate; others don't

[Hellyar]

Hello.

I note that some bones rotate with the Manipulate Bone Tool and others don't.

I've started learning all over again (but not using the support materials) by fiddling and seeing what happens.

I've drawn a typical multi-layered character with bones going down from the abdomen and bones going up from it. Where the two fat-ends of the bones meet, the lower one just shifts (with the artwork); not rotates.

Is there a rationale behind this, please?

[Hellyar]

I think I've fathomed this one out...

I put a bone going downwards ABOVE the character's head and then only use downwards bones throughout the character. This means that all the bones in the character rotate (i.e. plus artwork) and the one above the head - which doesn't rotate - can be ignored as not working properly.

[Hellyar]

Or, maybe this is it...

Where you have two bone fat-ends meeting, the one that is vertically above the other doesn't rotate.

And, if there's an end-fat-end (i.e. one without another vertically below it), that doesn't rotate, either.

[Hellyar]

It would appear that the first bone in a chain won't rotate using the Manipulate Bone tool.

But I'm not sure about this. It's possible to put bone constraint angles on it. That wouldn't be logical if it cannot rotate anyway.

[dueyftw]

If your on frame zero the mutilate bone tool will work only some times.

To test rigs, I always go down the time line to frame 1 or more. Use the rotate bone tool. Then return to frame zero to work on rigging.

Dale

[Hellyar]

GOT IT!

The first bone in a chain acts like an anchor on the stage. It cannot be rotated with the Manipulate Bones Tool. It can be translated with that tool and, if so, all the other connected bones (and artwork) translate with it. This is true even if several chains are attached to that single anchor bone.

The other bones in a chain can be rotated with the Manipulate Bones Tool - resulting in image manipulation/distortion - but cannot be translated with that tool.

The fat-end (origin?) of a non-anchor bone is the point of rotation.

Just one (non-facetious) question, please... if you have, say, six bones in a chain, what is the correct terminology for the anchor bone?... the great-great-great-great grandparent?

[slowtiger]

Root bone.

[Hellyar]

A good name. Thanks.